Lapping machine



Aug. 13, 1940. T, H, NYE r AL 2,211,729

LAPPING MACHINE Filed Jan. 13, 1939 3 Sheets-Sheet 1 THEODORE H.NYE \HERBERT 5.1NDGE T. H. NYE ET AL LAPPING MACHINE 3 Sheets-Sheet 2 Filed Jan. 13. 1939 3mm THEODORE H.NYE

HERBERT 5.1NDGE Aug. 13, 1940. 1'. H. NYE ET AL LAPPING ,MA'CHINE :5 Shee t s-Sheet 3 Filed Jan. 13, 1939 3mm THEODORE H.NYE

HEHBEHTE. INDEE FusuB Patented Aug. 13, 1940 UNITED STATES PATENT OFFICE.

LAPPING MACHINE Massachusetts Application January 13, 1939, Serial No. 250,794

7 Claims;

The invention relates to lapping machines-and with regard to its more specific features to machines for lapping external cylindrical surfaces.

One object of the invention is to provide a simple and practical machine for lapping pins or rolls, and by pins or rolls we mean any substantially cylindrical body of a single diameter or having its greatest diameter extending throughout the greater part of its length. Another object of the invention is to provide a machine of the character indicated for lapping long shafts. Another object of the invention is to provide a machine for any of the purposes specified above which is self-acting or automatic and requires only to be loaded. Another object of the invention is to provide a lapping machine for the lapping of pins, rolls or shafts which is continuous in action, has a simple cycle of operation, and delivers the work piece from the machine when the lapping operation is completed.

Another object of the invention is to provide a machine of the class indicated capable of being embodied in different forms for the achievement of a wide variation of lapping effects on pins, rolls and shafts by changing relative sizes of parts and adjustments thereof. Another object of the invention is to provide a centerless lapping machine in which the work driving elements are concave rather than convex and grip the work piece at a wide area of contact. Another object of the invention is to provide a centerless lapping machine having a soft regulating or feeding wheel. Other objects will be in part obvious or in part pointed out hereinafter.

wheel, its support, and some of the hones;

Figure 4 is a view of the feed wheeland sup-' port taken from the left of Figure 3;

Figure 5 is a view similar to Figure 1, showing some of the parts in vertical section;

Figure 6 is a front elevation of the machine, the plane of this figure being perpendicular to the axis of the work pieces and the regulating Wheels rather than vertical;

Figure 7 is a perspective view of one of the stands which supports the abrasive elements; and

Figure 8 is a sectional view taken along the 5 line 8-8 of Figure 6.

Referring first to Figures 1 and 2, we provide any suitable base In, preferably of fairly heavy construction, to provide a solid support for the machine. This base 10 is right and can be at- 10 tached to the floor of a building in any suitable manner. Extending upwardly from the base I0 is a bracket il in the form of a web which fits between a pair of integral webs l2 extending downwardly from the inside of a movable base I3, a trunnion pin l4 extending through the bracket II, and webs l2 pivotally supporting the movable base [3 on the stationary base It. By reason of this construction, the movable base l3 can be set at various angles to the stationary base In for purposes of adjustment, the movement being an angular one in a single plane. We further provide a web l5 integral with the base I3 and a clevis I6 with a pin H, the clevis l6 being integral with a screw shank 18. The screw shank l8 passes through a collar l9 having trunnions 20 extending at right angles to its axis which fit in a forked bracket 2| attached to the stationary base I0. A nut 22 with a hand wheel 23',is located on the threaded shank I8 and by turning the hand wheel 23, the shank l8 and, therefore, the movable base l3, can be raised and lowered. When the desired position of adjustment is found the parts can be locked together by means of a check nut 24.

Referring now to Figure 1, a plurality of stands, which are generally indicated by the numeral 26, are fastened to the movable base 13. Referring now to Figure 7, which shows one of these stands in perspective, each one comprises a web portion 21 which extends in a plane perpendicular to the top of the base l3. The various webs 21 are parallel to each other.

Still referring to Figure '7, extending normal to the web 21 on each side thereof is a rib 28.

These ribs 28 merge at the bottom with a base portion 29 of the stand 26 and. at the top with a heavy U shaped rib 30 which extends to both sides of the plane of the web 21. On the upper inside portions of the U shaped rib 30 are inclined plane surfaces 3| which form an acute dihedral angle with each other. The apex of this dihedral angle is parallel to the upper surface of the base I3 and is parallel to the axis of work piecesW, see Figure 1. Set into these surfaces 3| are abrasive sticks 32 whose upper abrasive surfaces 'are parallel to the planes of the surfaces 3| and whose greatest dimension lies parallel to the aforesaid apex of the dihedral angle. Referring to Figures 6 and 7, extending downwardly from the surfaces 3| of the U shaped rib 30 are flanges 35 leaving clearance spaced 36 between them and the outer wall of the U. These flanges 35 are parallel to each other and extend in a vertical plane. Weprovide floating abrasive carriers 40 which in cross section have the shape of an H 4| intercepted by a U 42 with a very wide bottom line.

- The uprights of the U 42 lie behind the flanges 35 and thus the floating abrasive carriers 40 maymove upwardly and downwardly and also may move in the direction of the axes of the work piece W but have no lateral motion. Referring to Figure 5, the upper ends of the H portion 4| of the carriers 4|! are closed by end walls 45 and thus the carriers 48 provide dish-like enclosures which receive abrasive holders 46 in which are cemented lapping sticks 41 of approximately rectangular parallelopipedal shape. The holders 46 fit snugly in the upper part of the H 4| and the holders may be adjusted upwardly by means of set screws 48.

Referring now to Figure 1 and also Figure 3, we provide a plurality of wheels 50, in this instance three. Each wheel 50 has a pulley rim 5| connected to a hub 52. Inside of each hub 52 is a rubber bushing 53. These wheels 50 are supported at times by the work pieces W but at other times, especially when the machine is idle and as it is about to start up, they are supported by rolls 55 which bear against driving belts 56 running in the pulley rims 5|, and the wheels 5|] are likewise supported by small rolls 5! which extend into the grooves in the pulley rims 5|.

As shown in Figure 5, the rolls 55 have trunnion ends and are supported in journalled' blocks 60 which are movable parallel to the ribs 28, being supported on one side by said ribs and on the other side, as shown in Figures 2 and 7, by parallel ribs 6| which are integral with the stands 26. The ribs 6| merge into bottom ribs 62 and thus, as indicated in Figure '7, the ribs 28 and 6| form the two sides of rectangular box-like frameworks, while the ribs 62 and the bottoms of the U shaped ribs 38 form the ends thereof. As is seen in Figure 1, such box-like frameworks are found on both sides of the central stands 26 while they are found only on the insides of the end stands 26. Adjustment bolts 83 enable the operator to raise or lower the blocks 8|! and,

therefore, the rolls 5,5 for proper adjustment of the wheels 50. In some cases, the rolls 55 contact the belts 56 but in other cases they may support the wheels 58 by direct contact with the pulley rims 5|. In Figure 2, they are shown in contact with both the belts and the rims.

In the case of the rolls 51, we provide, as shown in Figures 2, 6 and '7, integral ribs 65, 66 and 61 which together with part of the U shaped ribs 30 constitute rectangular boxes for the support of journal blocks 68 supporting the trunnion ends of the rollers 51, adjusting bolts 69 being provided for adjustment, as in the case of adjustment bolts 63. When the machine is in operation, the rubber bushings 53 are in contact with the upper surfaces of the work pieces W,

as clearly indicated in Figure 3, and as the work pieces themselves are definitely supported by the abrasive sticks 32, the wheels 50 are, therefore,

supported by the work pieces. The wheels 50, by means of the rubber bushings 53, rotate the work pieces W and thus the stationary abrasive elements 32 perform an abrading operation on the work pieces.

We provide means to oscillate the lapping sticks 41 by oscillating the H members 4|. As shown in Figures 2, 5, 6 and 8, springs 10 are anchored to the insides of the U shaped ribs 30 and rest in notches in the bottoms of the H shaped portions 4| of the carriers 40. The hubs 52 have, as best indicated in Figure 8, cam surfaces H which, as shown in Figure 3, contact the closed-over ends of the H portions 4|. Thus the'springs, which follow a curved contour as shown in Figure 8, tend to press the carriers -40 to the left (Figure 1) while the cams it are intermittently moving them in the opposite direction. The reacting thrust against the wheels 50 may be taken by split annular reaction plates 12 fastened to the U shaped portions 30 of the stands 26. This causes a reciprocation of the sticks 41 which effects a breakup of'the lapping action.

The abrasive sticks 32 and the lapping sticks 41 may be of the same abrasive composition or they may be of different abrasive compositions. They may be referred to as abrasive sticks or stones or lapping sticks. They may be made from any comminuted abrasive material bonded with any suitable bond and in varying grit sizes and abrasive structure. The abrasive may be of any known type, for example alumina in any of its forms including electric furnace fused alumina, the natural product such as emery or corundum, also any of the abrasive carbides, particularly silicon carbide, also diamonds. The bonding substance may be a synthetic resin or a vitrified glass or porcelain, or any ceramic product, or it may be a baked silicate of rubber or a natural resin such as shellac. Metallic bonds may also be used. The abrasive sticks or stones may be porous or not, as desired.

Referring to Figure 1, for support of the work pieces W prior to their entry into the bushings 53, we provide a trough 15 supported at one end by a bracket 16 extending upwardly from a motor bracket 11 that is""in turn fastened to the movable base l3. At the other end, the work pieces W are received by a trough 18 supported by a bracket 19 attached to the movable base l3. The other ends of the troughs 15 and 18 are preferably fastened to the stands 26.

Still referring to Figure 1, for driving the wheels 50, we provide a motor 8|) supported on the stand 11. Comparing now Figures 1 and 6, a pulley 8| fastened to the armature shaft of the motor drives a belt- 82 which drives a pulley 38 fastened to a shaft 84 journalled in a stand 83 fastened to the movable base l3. This shaft extends through journals provided in brackets 83 fastened to the movable base l3 and on the shaft 84 are pulleys 84a (see Figures 1 and 2) which drive the belts 56. We may provide idler pulleys 85 contacting the belts 56 to keep them taut. Such idler pulleys are shown in Figure 2 as mounted on the ends of arms 86 pivoted in the wheels 50. As shown in Figures 1,2 and 6, a long shaft 90 is supported in stands 92 on the tops of the stands 26. This shaft 90 supports arms 93 having forked ends 94 pivotally holding bushings 95 receiving rods 96 the bottom ends of which are connected by clevises 91 to arms 88 pivotally mounted on the stands 92 and supporting rollers 99 in contact with the workpieces W. On each rod 96 is a spring I so that when the bushings 95 are depressed the springs are compressed to urge the rollers 99 against the work pieces W with greater force.

The arms 98 can be adjustably held in various positions by means of a hand lever IOI fastened to the shaft 90 which has a hand grip lever I02 connected by a link I03 to a pawl I04 pivoted at I on the lever IN, the pawl I04 engaging a ratchet segment I06 to hold the shaft 90 at any angular position. By squeezing the hand grip portion of levers IN and I02 the pawl can be released.

In operating the machine the lever IN is first manipulated to move the rollers 99 away from the path of the work pieces, there being heads on the upper ends of the rods 96 so that the arms 93 may lift the rods. Work pieces W are then placed in the trough I5 and'moved in the bushings53 by gravity. Then the lever IOI can be manipulated to bring a roll 99 against the Gravity is relied upon to move the machine and it is noted that the spring pressures are light and either the rolls or the abrasive stones are bevelled at the ends, preferably both. Where it is desired to use greater pressures a ram can be used to drive the work pieces W through the machine.

By reason of the oscillating motion described, a fine lapping action is effected on the work pieces and the machine is, nevertheless, continuous in operation. When light lapping pressures are employed adjustment of the rate at which the work pieces go through the machine can be effected by means of the hand wheel 23 which changes the angle of inclination of the trough I5.

While rubber bushings 53 have been described, other substances can be used and for some purposes the work drive can be be effected by contact of the interior cylindrical surface of a metal wheel with the work piece.

It will be seen that the abrasive stones will be cut by imaginary planes tangent to the inside of the bushing. These stones have surfaces which are closer to the center of the axis of the wheels than the bottom part of the inner circles of the bushings due to the fact that the bushings are slightly oversized in order that the work piece may not stick therein. However the abrasive surfaces of the sticks or stones 41 are substantially or approximately tangent to the circle of the bushings 53.

It will thus be seen that there has been provided by this invention-an apparatus in which the various objects hercinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth, or shown in the accompanying drawings, is to be interpreted as illustrative and not in a limiting sense.

We claim:

1. Apparatus of the class described comprising a wheel having a work gripping bushing, abrasive stones in planes approximately tangent to the inner circle of the bushing, and means to free work piece rolls into the bushing and past the abrasive stones thereby to abrade the work pieces.

2. In apparatus of the class described, a wheel, a work gripping bushing at the center of the wheel, means to rotate the wheel, an abrasive stone having an abrasive surface approximately tangent to the inner circle of the bushing throughout and means to vibrate the abrasive stone whereby to lap a work piece passing through and rotated by the bushing.

3. In apparatus of the class described, a work piece rotating wheel having an internal surface of revolution for contact with a cylindrical work piece, means to rotate the wheel on the axis of said surface of revolution, a pair of abrasive stones rigidly held and which are cut by planes tangent to the said surface, a third abrasive stone also cut by a plane tangent to the surface, and means to vibrate the third stone.

4. In apparausoi the class described, a generally U-shaped frame, abrasive sticks received in the frame, a wheel having an internal surface of revolution, means peripherally supporting said wheel, means to rotate the wheel on the axis of said surface of revolution, and means to bring cylindrical work pieces to the internal surface of the wheel and into contact with the abrasive sticks, the workpieces being held against the sticks by the wheel.

5. In apparatus as claimed in claim 4 the combination with the parts and features therein specified of an additional abrasive stick, and means to oscillate it axially of the work piece.

6. In apparatus as claimed in claim 4 the combination with the parts and features therein specified of a roller on an axis parallel to the axis of the wheel and means to urge the roller towards the axis of the wheel to urge the work piece against the abrasive sticks.

'7. In apparatus of the class described, a work feeding trough, a plurality of wheels in axial alignment, means to drive the wheels, bushings centrally fixed in the wheels and coaxial therewith, and fixed abrasive stones adjacent to the ends of the bushings having surfaces spaced by a substantial distance from the common axis of the wheels whereby work pieces passing through the bushings are rotated thereby and abraded by the abrasive stones.

THEODORE H. NYE. HERBERT S. INDGE.

CERTIFIQATE 0F CORRECTION.

August 15, 19140. I THEODORE H. NYE, ET AL.- It is hereby certifiedthat error appears in the prinised specification Patent Ne. 2,211,729;

of theebove numbered patent requiring correctionas follows} Page 5; sec- 0nd ool'umn,' line l2, cleim .1, for the'word free'f read "feed"; and that the said Letters Patent shonld be read with this correction-thereinthat the same may. conform to the record of the case in the. Patent Office.

Signed and sealed this 22nd day of illy, A.*D 191m.

Henry Van Aredale (Seal) Acting Commissioner of Patents. 

